*2.6. Transparency and Color Analysis*

The transparency of the edible films is an important parameter as it affects the visual appearance of the food products. The percentage transparency values varied significantly (*p* < 0.05) from 90.37 to 82.80% with the addition of oil in the films. The transparency of the control film (B) was highest, while the film sample, PC40 with the highest concentration of oil exhibited the lowest transparency. The reduction in transparency after the inclusion of MOEO may be attributed to the presence of colorful constituents within the oil [20]. The results of the current investigation are consistent with those reported by Scartazzini et al. [26], wherein a decrease in transparency was noted upon the incorporation of mint essential oil into films.

The color parameters of different film samples loaded with varying concentrations of MOEO are presented in Table 3. The lightness (*L*\*) of the film samples slightly increased with higher MOEO concentration, but there were no significant differences observed in the values of the lightness of different samples. The inclusion of MOEO resulted in notable changes in the yellowness (*b*\*) (0.95–1.57) of the film samples. The increase in the yellow color may be associated with the existence of various pigments within MOEO. Furthermore, a significant difference was detected in the *a*\* redness values of the film samples. In addition, a higher ∆*E*\* value was associated with a higher amount of MOEO; for instance, PC40 had the highest value of ∆*E* (1.90), and B film (control film) had the lowest value (0.85). These results demonstrated that the addition of MOEO changed the color characteristics of pectincollagen-based composite films. Similar findings were reported by Al-Harrasi [20] et al., indicating that the incorporation of essential oil increased the yellowness of the edible films.


**Table 3.** Color parameters of different edible film samples loaded with MOEO.

The values with different letters (a, b, c, and d) inside a column indicate significant differences (*p* < 0.05). *L*: lightness, *a*\*: green-red color, *b*\*: blue-yellow color, and ∆*E*\*: overall color variation.
